Conventionally, line production systems of a human-and-robot collaborating type are proposed for assembling process of electric and/or electronic components, etc., in which workers and work robots stationed serially along a conveyance line of workpiece collaborate. For example, Patent Document 1 discloses a dual-arm work robot used for the human-and-robot collaborating type line production system.
The dual-arm work robot of Patent Document 1 includes a main body, a head, two arms, a hand attached to respective tip-ends of the arm, and a carriage which supports a lower part of the main body. A lower part of the carriage has four fixed legs, two swivel casters located at a rear side of the carriage and two driving wheels located at a front side of the carriage. A state of this carriage can be switched between a movable state by being supported by the casters and the driving wheels and a positionally fixed state by being supported by the fixed legs. Further, each of the driving wheels is connected to a traveling drive motor provided with a clutch and controlled by a controller (control box). A state of the driving wheels is switchable between a freely-rotatable state by disengaging the clutch and a driving state by being connected to the traveling drive motors and driven thereby.
When installing the dual-arm work robot with the above structure on a workbench, an operator manually pushes the carriage supported by the freely-rotatable driving wheels to the workbench and then fixes the position of the carriage. If the robot moved during the work and requires a correction in the work position, the controller controls the arms to extend and engage anchor pins provided at tip portions of the arms with anchor points provided to the workbench, switches the carriage to the state supported by the freely-rotatable driving wheels, and pulls the extended arms to move the carriage to a desired work position. When the correction amount of the work position is large, the controller switches the carriage to the state supported by the driving wheels, and drives the driving wheels with the traveling drive motors to cause the carriage to travel, so as to move the carriage to the desired work position.